Host specificity of Salmonella weltevreden typing phages.

The host range of the six S. weltevreden typing phages was studied on 1469 strains belonging to 37 different Salmonella serotypes. In addition to S. weltevreden, only S. nchanga, S. give, S. lexington and S. anatum, all belonging to O group E, showed varying degrees of susceptibility to the action of some of the typing phages. Typing phage VI lysed only one strain other than S. weltevreden. All serotypes tested other than S. weltevreden were resistant to phages III and IV even at 1000 times the routine test dilution. Thus, typing phages III and IV were specific for S. weltevreden. The sensitivity patterns of S. weltevreden typing phages were not found to bear much correlation with either somatic of flagellar antigens of Salmonellae.